[unix-pc.general] yet again Re: crontab Daemon-from-Hell

levy@cbnewsc.ATT.COM (Daniel R. Levy) (06/11/89)

In article <1545@sialis.mn.org>, rjg@sialis.mn.org (Robert J. Granvin) writes:
[about uudemon.day]
> The solution is VERY simple.  Remove the `cd`, and make the find
> reference an explicit path.  If the directory dies or goes away, the
> find will fail, and nothing more will happen than your uucp mailfile
> getting a note of the failure.

Could someone please tell me if my postings on this group are getting out?

Twice this past week I mentioned that a failed 'cd' (due to, for example,
the directory named as the argument to 'cd' not being present) would ABORT a
script running under /bin/sh, uucpadm's default shell.

This is UNLIKE what happens in an interactive shell session, where the shell
does not abort upon a failed 'cd' but simply stays in the directory where it
was before the failed 'cd'.

Unless there is some reason that the uudemon.day isn't running under stock
/bin/sh (e.g., you installed your own version of /bin/sh which does not
abort scripts upon a failed cd, or installed /bin/ksh in place of /bin/sh,
or gave uucpadm a shell of /bin/ksh in /etc/passwd [why? when it's not
an account meant to be logged into directly]) there is NO DANGER of the stock
uudemon.day wiping out anything other than 30-day-old contents of
/usr/spool/uucppublic.  Please folks, don't holler at AT&T for this....

I apologize for sounding exasperated.  I assume that my posts just haven't
gotten to Robert's site yet.  Are they getting out at all?
-- 
Daniel R. Levy             UNIX(R) mail:  att!ttbcad!levy, att!cbnewsc!levy
AT&T Bell Laboratories
5555 West Touhy Avenue     Any opinions expressed in the message above are
Skokie, Illinois  60077    mine, and not necessarily AT&T's.

rjg@sialis.mn.org (Robert J. Granvin) (06/11/89)

>> The solution is VERY simple.  Remove the `cd`, and make the find
>> reference an explicit path.  If the directory dies or goes away, the
>> find will fail, and nothing more will happen than your uucp mailfile
>> getting a note of the failure.
>
>Could someone please tell me if my postings on this group are getting out?
>
>Twice this past week I mentioned that a failed 'cd' (due to, for example,
>the directory named as the argument to 'cd' not being present) would ABORT a
>script running under /bin/sh, uucpadm's default shell.
>
>I apologize for sounding exasperated.  I assume that my posts just haven't
>gotten to Robert's site yet.  Are they getting out at all?

Yes, they're getting here.  However, I should have clarified a point
(just like I noted that the original posting didn't clarify the point
:-).

This made the exact point that I failed to...

There are more than a few people who insist upon changing default
shells away from /bin/sh to other shells including ksh and others.

Prudent or wise?  Your decision.  (Although a real cron will warn you
that the commands will be executed with /bin/sh.  What does a stock
3b1 do if you change your default shell and run a cron job?)

However, if run as ksh, the failed cd will NOT cancel the execution of
the script.  So, even if safe under a cron job, it may not be safe
under a manually executed job.

And since so many people are panicking about it and beating it into
the ground (which was a point I _did_ make), then just "solve" it and
quit letting it eat your cerebral cortex.  Seeing everything from
comments about "reprehensible" to lawsuits, it's just not worth
discussing it anymore since people are just not thinking rationally
about it.  Just fix it, and "Don't worry, be happy."

-- 
________Robert J. Granvin________   INTERNET: rjg@sialis.mn.org
____National Computer Systems____   CONFUSED: rjg%sialis.mn.org@shamash.cdc.com
__National Information Services__       UUCP: ...uunet!rosevax!sialis!rjg
                 "Exxon: Our gasoline contains no sea water"

seg@PacBell.COM (S. E. Grove) (06/13/89)

>Could someone please tell me if my postings on this group are getting out?
>
Yes. You got to me.
	Stephen Grove  pacbell!pbhya!seg

thad@cup.portal.com (Thad P Floryan) (07/22/89)

Both Karl Botts and Robert Granvin bring up good points.  And, yes, the issue
of uudemon.day deleting files IS getting tedious.

HOWEVER:  I've been reading this newsgroup for 2 years and have archived
nearly everything, and not once before has the matter of files disappearing
at 4AM daily been brought up (to my recollection.)

My original posting served to alert people to that fact of Unix life, and
I received over 20 emails thanking me for the posting.

From my displays at the West Coast Computer Faire, discussions in the local
UNIXPC SIG of the AT&T Users' Group, and from other chance meetings of fellow
UNIXPC'ers, it's clear to me that MOST owners/users of UNIXPC systems are
simply not aware of such things being done TO them (by the crontab scripts and
whatever else.)

If one had the $$$ for a formal UNIX education, I'm sure the $2,000/week
classes that one attended informed YOU of these "problems."  But the main
reason I bought my UNIXPC (in 1987) was to teach myself UNIX for LESS than
the cost of a single class, and have the hardware as an added benefit.

I've used over 50 different computer systems in the 25+ years I've been
involved with computing, and can pick up on a "new" system quickly; I now
consider myself moderately proficient with UNIX, and learn more daily by
teaching/helping others with their systems.  The UNIX credo of "build upon
the work of others" is something I practice and teach.  A forum such as this
one is one in which we all help each other.

The tone of yet another posting suggested "cut out the crap" and deal with
only the technical issues.  I disagree.  New readers are always entering
this forum.

My $.02 ...


Thad Floryan [ thad@cup.portal.com (OR)  ..!sun!portal!cup.portal.com!thad ]

bob@rush.cts.com (Bob Ames) (08/03/89)

In article <19560@cup.portal.com> thad@cup.portal.com (Thad P Floryan) writes:
>Both Karl Botts and Robert Granvin bring up good points.  And, yes, the issue
>of uudemon.day deleting files IS getting tedious.
>
>HOWEVER:  I've been reading this newsgroup for 2 years and have archived
>nearly everything, and not once before has the matter of files disappearing
>at 4AM daily been brought up (to my recollection.)

David Solan (kdavid@gizzmo.UUCP) posted on this subject about 1 year ago.

He also goes into this at length in "Objective Utilities", a software
package for the UNIX PC which includes nice things like Unremove,
Blinkoff, utilities to optimize file placement on hard drives, lots
of documentation on Unix PC filesystem bugs, etc.

I think Objective Utilities sells for around $125.00.

If you`ve ever deleted a file and immediately wished it would return,
type Unremove!

"I don`t work for Objective Programming (201-866-6900), I`m just a satisfied
customer."

Bob

Bob Ames   The National Organization for  the Reform of Marijuana Laws, NORML 
"Pot is the world's best source of complete protein, alcohol fuel, and paper,
is the best fire de-erosion seed, and is america's largest cash crop." - USDA
bob@rush.cts.com or ncr-sd!rush!bob@nosc.mil  or rutgers!ucsd!ncr-sd!rush!bob
619-741-UN2X "We each pay a fabulous price for our visions of paradise," Rush

cks@ziebmef.uucp (Chris Siebenmann) (08/18/89)

thad@cup.portal.com (Thad P Floryan) writes (in a really ancient
 article I should have replied to long ago):
| From my displays at the West Coast Computer Faire, discussions in the local
| UNIXPC SIG of the AT&T Users' Group, and from other chance meetings of fellow
| UNIXPC'ers, it's clear to me that MOST owners/users of UNIXPC systems are
| simply not aware of such things being done TO them (by the crontab scripts and
| whatever else.)

 Congratulations; you've just learned another lesson of Unix system
administraion. One should *always* look at the automated scripts that
ye spiffy Unix system wants to run; from crontab, on startup, in
/etc/profile, in /etc/inittab. One usually finds out some quite
interesting and often important information, and one avoids nasty
surprises (like that fsck -y that's probably *still* in people's
/etc/rc; send email for a copy of my article about why this is a Real
Bad Idea and how to fix it).

[For example, take a look at /etc/cleanup.wk -- it shows you how to
 get smgr to empty out /usr/adm/cronlog, for example (and it removes
 week-old core files for you, and other functions).]
-- 
"Would that Aza Chorn had teleported Bates elsewhere and not removed
 so charming and preposterous a folly from our skyline ... but then he
 could not have known, not being raised around these parts."
Chris Siebenmann		uunet!{utgpu!moore,attcan!telly}!ziebmef!cks
cks@ziebmef.UUCP	     or	.....!utgpu!{,ontmoh!,ncrcan!brambo!}cks